1. Field of the Invention
The present invention relates to a composition usable for the prevention and treatment of E. coli infections which comprises a bacteriophage isolated from the nature and having a broad antibacterial spectrum against E. coli, and a method for preventing and treating E. coli infections using the same. More precisely, the present invention relates to a bacteriophage comprising the partial nucleotide sequences represented by SEQ ID NO: 1 to SEQ ID NO: 25, a composition for the prevention and treatment of E. coli infections comprising the said bacteriophage as an active ingredient, and a method for preventing and treating E. coli infections using the said composition.
2. Description of the Related Art
E. coli is Gram-negative intestinal bacteria belonging to bacillus. Most of E. coli are residential flora which means they are not pathogenic bacteria, yet. But, E. coli O157:H7 or ETEC (enterotoxigenic E. coli) are pathogenic bacteria that cause food poisoning in human or diarrhea in animals such as cow, pig, and goat, etc. Pathogenic E. coli can produce heat-labile enterotoxin (LT) that loses its activity when it is heated at 60° C. for 10 minutes, or heat-stable enterotoxin (ST) that exhibits resistance against heat and is stable at 100° C. upto 30 minutes.
Among the pathogenic E. coli, ETEC strains have been an issue that cause serious problems in livestock industry, particularly they cause diarrhea in newborn piglets or weaning pigs. Particularly, E. coli K88 strains, E. coli K99 strains, E. coli 987P strains, and E. coli F41 strains are known as the major enterotoxigenic E. coli types.
Considering a significant damage in livestock industry by such E. coli, it is urgently requested to develop a method for preventing or treating E. coli infections. A variety of antibiotics have been used to prevent or treat such pathogenic E. coli infections. However, according to the recent rise of antibiotic-resistant bacteria, an efficient alternative is urgently requested.
Recently, the use of bacteriophages has drawn our attention as a new way of treating bacterial infections. Particularly, the reason of our high interest in bacteriophages is because bacteriophage-based treatment is a nature-friendly method. Bacteriophages are an extremely small microorganism that infects bacteria, which are called phage in short. Once bacteriophage infects bacteria, the bacteriophage is proliferated in the inside of the bacterial cell. After full proliferation, the progenies destroy the bacterial cell wall to escape from the host, suggesting that the bacteriophage has bacteria killing ability. The bacteriophage infection is characterized by high specificity, so that a certain bacteriophage infects only a specific bacterium. That is, the bacterium that can be infected by certain bacteriophage is limited, suggesting that bacteriophage can kill only a specific bacterium and cannot harm other bacteria.
Bacteriophage was first found out by an English bacteriologist Twort in 1915 when he noticed that Micrococcus colonies melted and became transparent by something unknown. In 1917, a French bacteriologist d'Herelle found out that Shigella disentriae in the filtrate of dysentery patient feces melted by something, and further studied about this phenomenon. As a result, he identified bacteriophage independently, and named it as bacteriophage which means a bacteria killer. Since then, bacteriophages specifically acting against such pathogenic bacteria as Shigella, Salmonella typhi, and Vibrio cholerae have been continuously identified.
Owing to the unique capability of bacteriophage to kill bacteria, bacteriophages have been studied and anticipated as a method to treat bacterial infections. However, after penicillin was found by Fleming, studies on bacteriophages had been only continued in some of Eastern European countries and the former Soviet Union because of the universalization of antibiotics. After the year of 2000, the merit of the conventional antibiotics faded because of the increase of antibiotic-resistant bacteria. So, bacteriophages are once again spotlighted as a new anti-bacterial agent that can replace the conventional antibiotics.
According to the recent regulation of use of antibiotics by the government, the interest on bacteriophages increases more and more.
Thus, the present inventors tried to develop a composition usable for the prevention or treatment of E. coli infections by using a bacteriophage isolated from the nature and displayed a broad antibacterial spectrum against E. coli strains including E. coli K88 strains, and further tried to develop a method for preventing or treating E. coli infections using the said composition. As a result, the inventors succeeded in isolating an effective bacteriophage from the nature that displayed a broad antibacterial spectrum against E. coli strains and identified the partial nucleotide sequences of the genome of the isolated bacteriophage that could distinguish the isolated bacteriophage from previously reported bacteriophages. Based on that, the present inventors developed a composition comprising the isolated bacteriophage as an active ingredient and further confirmed that this composition could be efficiently used for the prevention and treatment of E. coli infections, leading to the completion of this present invention.